There is NO question that spending time with a person who is a real authority in a given field gives the benefits that nothing else can give. But, these benefits are varied and there are many factors related to this that need to be considered properly. It is NOT a pill!
One has to know what kind of benefit one needs or wants. Suppose one wants to develop a regular practice of yoga exercise or even meditation. Then, a company of other yoga exercise students who have performed such an activity for say 5 years regularly will be as effective as any maestro in the world. In other words, you do not an airplane to go to a corner grocery store. In fact, the car will do a better job!
If one thinks that only by company of a particular person, some spiritual vibrations are going to enter into you and you are going to be transformed, then one must actually have that kind of feeling towards that person. Also, they should not do it as a trial and error like we do with Sun Salutations. And, if they are not sure about such a person, they should NOT do it. Because, it will most likely be dangerous to them. Vibrations shall only shatter their personality!
On the other hand, if one meets a real maestro, and one gets a chance to spend time with him/her, and one does not make use of that opportunity, such a student is the most foolish one. And, a great opportunity is wasted.
Anyway, above three examples give an idea of what I want to say. If correctly combined and used, the company of a real maestro, which automatically includes real student produces the fastest progress in Yoga!